What happens in our brains when we learn and remember? Are memories recorded in a stable physical change, like writing an inscription permanently on a clay tablet?
Prof. Yadin Dudai, Head of the Weizmann Institute's Neurobiology Department, and his colleagues are challenging that view. They recently discovered that the process of storing long-term memories is much more dynamic, involving a miniature molecular machine that must run constantly to keep memories going. They also found that jamming the machine briefly can erase long-term memories. Their findings, which appeared August 16 in the journal Science, may pave the way to future treatments for memory problems.
Science & Technology
A recent study showed that the U.S. and China are the nations most vulnerable to a devastating meteorite strike. With funding uncertain, astronomers are struggling to contain the threat of a civilization-ending galactic visitor.
The North Atlantic is stirring fitfully. A new monitoring system has shown that the ocean's currents change rapidly, surging or slowing from one week to the next. That makes it difficult to judge whether they really are slowing down over the long term, as one study has suggested.
A pair of German physicists claim to have broken the speed of light - an achievement that would undermine our entire understanding of space and time.
This incredible picture shows a star with an unusual trait - a glowing, comet-like tail which extends an incredible 13 light years back into space.
The star itself, called Mira, is about 350 light years from Earth.
As the star hurtles through space its tail is shedding carbon, oxygen and other important elements needed to form new stars, planets and possibly even life.
The star itself, called Mira, is about 350 light years from Earth.
As the star hurtles through space its tail is shedding carbon, oxygen and other important elements needed to form new stars, planets and possibly even life.
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| ©Unknown |
It resembles a hand-held electric razor and is available in metallic pink, electric blue, titanium silver and black pearl.
But it gives out a 50,000-volt jolt that short-circuits brain signals and momentarily incapacitates.
But it gives out a 50,000-volt jolt that short-circuits brain signals and momentarily incapacitates.
Archaeologists using radar imagery have shown that an ancient Cambodian settlement centered on the celebrated temple of Angkor Wat was far more extensive than previously thought, a study released Monday said.
The medieval settlement surrounding Angkor, the one-time capital of the illustrious Khmer empire which flourished between the ninth and 14th centuries, covered a 3,000 square kilometer area (1,158 square miles).
The urban complex was at least three times larger than archaeologists had previously suspected and easily the largest pre-industrial urban area of its kind, eclipsing comparable developments such as Tikal a Classic Maya "city" in Guatemala.
The medieval settlement surrounding Angkor, the one-time capital of the illustrious Khmer empire which flourished between the ninth and 14th centuries, covered a 3,000 square kilometer area (1,158 square miles).
The urban complex was at least three times larger than archaeologists had previously suspected and easily the largest pre-industrial urban area of its kind, eclipsing comparable developments such as Tikal a Classic Maya "city" in Guatemala.
Israeli archaeologists have discovered a footprint possibly made by the sandal of a Roman legionnaire in the ruins of the ancient town of Sussita, in northern Israel, the Haaretz newspaper said Wednesday.
The hobnailed sandal might have belonged either to someone involved in building works or to a Roman soldier, the scientists from Haifa University said.
The hobnailed sandal might have belonged either to someone involved in building works or to a Roman soldier, the scientists from Haifa University said.
Most newborn stars are gluttons, feeding on afterbirth of dust and gas long after igniting.
Although this accreting activity doubles stellar surface temperatures by burning up the material, it mysteriously softens the emission of high-energy X-rays.
"Accreting stars have three times less X-ray emission than non-accreting stars, which seems unusual," said Kevin Briggs, an astrophysicist at the Swiss Federal Institute of Technology in Zurich, Switzerland.
Now Briggs and several teams of researchers have discovered why some stars' X-ray profiles are so thin: The nebulous surroundings of a young star absorb the extra energy produced by falling into it.
Although this accreting activity doubles stellar surface temperatures by burning up the material, it mysteriously softens the emission of high-energy X-rays.
"Accreting stars have three times less X-ray emission than non-accreting stars, which seems unusual," said Kevin Briggs, an astrophysicist at the Swiss Federal Institute of Technology in Zurich, Switzerland.
Now Briggs and several teams of researchers have discovered why some stars' X-ray profiles are so thin: The nebulous surroundings of a young star absorb the extra energy produced by falling into it.
New scientific findings suggest that a large comet may have exploded over North America 12,900 years ago, explaining riddles that scientists have wrestled with for decades, including an abrupt cooling of much of the planet and the extinction of large mammals.
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| ©Allen West, UCSB |
| A "black mat" of algal growth in Arizona marks a line of extinction at 12,900 years ago; Clovis points and mammoth skeletons were found at the line but not above it. |
Comment: Just in this last week it was discovered that the 10 hottest years on record did not all fall within the last 15 years as previously promoted. It turns out that an alleged Y2K bug was to blame.
See Global Warming Debate Reignited After NASA Quietly Corrects Temperature Data